1. Field of the Invention
The present invention relates to a novel strain of Bacillus licheniformis, in particular to a zearalenone (ZEN)-detoxifying Bacillus licheniformis CK1 (DSM 025954).
2. The Prior Arts
Fungal toxin is a major problem in cereal grains throughout the world, which causes the health problems for human and livestock, and huge economical losses. These toxins include aflatoxins, fumonisins, ochratoxins, tremorgenic toxins, trichothecenes, and zearalenone. Zearalenone (ZEN) is a potent non-steroid estrogenic metabolite, produced by the Fusarium graminearum, F. culmorum, F. cerealis, F. equiseti, F. crookwellense and F. semitectum common in soil in warm areas. Zearalenone causes reproductive disorders and has been implicated in hyperoestrogenic syndromes in humans. Though ZEN was not classified by the WHO-International Agency for Research on Cancer (IARC) in group 3, not classifiable as to its carcinogenicity to humans, it was reported to be hepatotoxic, hematotoxic, immunotoxic and genotoxic in studies.
Many studies have focused on the tests for the above mentioned mycotoxins to prevent the contamination on products. However, the best solution is to remove the toxins through biochemical degradation, which may retain the nutrition and flavor in a mild detoxifying way without using harmful chemicals.
Application of microorganisms in degradation of the toxin in foods or feeds is a well known technology. Biological detoxification can be used to decrease or remove contamination of mycotoxins in a highly efficient, specific and non-environmental affecting way. There are two applications in treating fungi contaminated foods or feeds: mycotoxins biodegradation and inhibition of absorption of mycotoxins. Butyrivibrio fibrisolvens, Gliocladium roseum, Trichosporon mycotoxinivorans and some rumen protozoa can degrade the mycotoxins into non-toxic or slightly toxic products. Lactobacillus rhamnosus and Saccharomyces cerevisiae can inhibit absorption of mycotoxins through binding to the cell walls of microorganisms in the gastrointestinal tract.
Bacillus licheniformis is a saprophytic bacterium that is widespread in nature. The enzymes of Bacillus licheniformis for industrial production include amylase and protease. According to previous studies, they have great potential to be used as beneficial microorganisms for human or feed supplements. Researchers have reported that Bacillus licheniformis increased the function of immune systems, increased weights, decreased the chance of diarrhea in mice and improved the feed-conversion efficiency in pigs when used as beneficial microorganisms. In addition, Bacillus licheniformis was found to inhibit the growth of Aspergillus and degrade aflatoxins B1 (AFB1) and ochratoxins A (OTA). However, there is no report regarding the application of Bacillus licheniformis in detoxifying zearalenone.